Biomechanics on the mechanical adaptation of biological tissues at the microstructural level

我们提出了一种新的方法，用相差显微镜或差示干涉显微镜观察未经化学处理的胶原蛋白束的微观结构，并研究了从小鼠尾腱获得的胶原束的微观结构与力学性能之间的关系。为了进行力学测试，在显微镜上安装了专门设计的微拉伸试验机。用氰基丙烯酸酯粘合剂将小丙烯酸块附着在每个神经束的两端。其中一个块固定在称重传感器上，另一个固定在线性执行器的十字头上。将神经束浸入生理盐水中，夹在载玻片和盖玻片之间。以0.1 mm/sec的速度移动致动器将试样拉伸至失效。用显微镜观察神经束的微观结构，并用数字录像机记录图像。显微镜下，胶原纤维束以典型的平行方式排列在神经束中。在无负载的情况下，束具有周期性卷曲模式。在荷载-变形曲线的线性区域，纤维平行矫直。在荷载突变减小之前，观察到部分纤维的部分断裂。

We developed a new method by which tensile tests were performed observing the microstructure of the chemically non-treated raw collagen fascicles with a phase-contrast microscope or differential interference microscope, and studied the relationships between the microstructure and mechanical properties of fascicles obtained from the mouse tail tendon.For mechanical testing, a specially designed micro tensile tester was mounted on a microscope. Small acrylic blocks were attached to both ends of each fascicle with cyanoacrylate adhesives. One of the blocks was fixed to a load cell, and the other one was fixed to the crosshead of a linear actuator. The fascicle was immersed in a saline solution and sandwiched between a slide glass and cover glass. The specimen was stretched to failure by moving the actuator at the speed of 0.1 mm/sec. The microstructure of the fascicle was observed using the microscope, and the images were recorded on a digital video recorder.Microscopically, the bundles of collagen fibers arranged in a typical parallel fashion were observed in the fascicles. Under no load, the bundles had a periodic crimp pattern. At the liner region of load-deformation curve, the fibers were straightened in parallel. Before the catastrophic decrease of load, the partial rupture of some fibers was observed.